Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bcl-2/IgH rearrangement is the molecular hallmark of follicular lymphoma (FL) which is present in 70-90% of the cases at diagnosis. The clinical significance of this feature is controversial. The aim of this study was to analyze the bcl-2/IgH rearrangement by means of a PCR technique, and to correlate molecular findings with clinical characteristics and outcome. Sixty-nine patients (median age, 53 years; male/female ratio: 35/34) diagnosed with FL in a single institution were included in the study. A total of 77 DNA samples were analyzed, 54 were obtained from lymph node biopsy and 23 from peripheral blood or bone marrow. Bcl-2/IgH rearrangement was assessed for both the major breakpoint region (MBR) and the minor cluster region (mcr) breakpoints by a PCR technique. Thirty-nine out of sixty patients (65%) with assessable samples were found to have a bcl-2/IgH rearrangement in the MBR breakpoint, whereas bcl-2/IgH rearrangement in mcr was observed in one patient (2%) and no rearrangement at MBR or mcr in the remaining 20 patients (33%). Regarding the initial characteristics, patients with bcl-2/IgH rearrangements at MBR or mcr were younger (<65 years) than those with no rearrangement at these sites (p = 0.0001). No differences were found according to bcl-2/IgH rearrangement in terms of complete response rate, time to treatment failure and overall survival. In our series bcl-2/IgH rearrangement at MBR or mcr, which was found in 67% of the patients, was not correlated with response to treatment, survival nor time-to-treatment-failure.
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PMID:Incidence and clinical significance of bcl-2/IgH rearrangements in follicular lymphoma. 1269 Nov 44

Occasionally, primary large B-cell lymphomas (LBLs) arising in the spleen present with a micronodular pattern involving the splenic white pulp but sparing the red pulp. Histologically, the nodules contain scattered large B cells in a background of numerous T cells and histiocytes. They can cause substantial difficulty in histologic diagnosis as the morphology can mimic reactive and inflammatory lesions as well as other lymphoid neoplasms. In this study, we examined the histology and immunophenotype of the micronodular T-cell/histiocyte-rich LBL (MTLBL) of the spleen with a view to establish the characteristics that may be helpful in diagnosis. Paraffin-embedded material from 17 cases of MTLBL was studied. Clinical features and histology were reviewed and immunohistochemistry was performed for immunoglobulins, CD20, CD79a, CD3, CD68, CD10, BCL6, BCL2, OCT-2, epithelial membrane antigen, CD30, CD138, and EBV markers. The median age of presentation was 56 years, and the most frequent presenting features were anemia and B symptoms. All cases showed a micronodular pattern of involvement. The tumor nodules comprised a mixture of numerous CD3+ T cells and CD68+ histiocytes and scattered large CD20+ B cells with immunoglobulin light chain restriction. They were positive for BCL6 and OCT2 but negative for CD10, CD138, and EBV markers. There was variable expression of epithelial membrane antigen, Bcl-2, and CD30. No follicle dendritic cell meshwork infrastructure underlying the nodules could be demonstrated by staining for CD21 or CD35 antigens. The prognosis was poor; seven of the 12 cases with follow-up were dead within 2 years. MTLBL is unique variant of T-cell/histiocyte-rich diffuse LBL, characterized by primary splenic presentation and a micronodular architecture. The main differential diagnoses include granulomatous inflammation, Hodgkin's lymphoma, follicular lymphoma, and peripheral T-cell lymphomas.
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PMID:Micronodular T-cell/histiocyte-rich large B-cell lymphoma of the spleen: histology, immunophenotype, and differential diagnosis. 1282 82

bcl-xL, a member of the Bcl-2 family, exerts an antiapoptotic effect on lymphocytes. To assess its clinical significance in patients with follicular lymphoma, realtime quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of bcl-xL gene expression was investigated in whole lymph node sections and laser-microdissected lymphoma cells of 27 patients. Compared with 10 patients with reactive follicular hyperplasia, the bcl-xL gene was overexpressed in patients with follicular lymphoma at a higher level in microdissected lymphoma cells. The bcl-xL gene level correlated with the number of apoptotic lymphoma cells labeled by terminal deoxytransferase-catalyzed DNA nick-end labeling (TUNEL) assays (r = -0.7736). Clinically, a high bcl-xL level was significantly associated with multiple sites of extranodal involvement (P =.0020), elevated lactate dehydrogenase level (P =.0478), and an International Prognostic Index indicating high risk (P =.0235). Moreover, bcl-xL gene overexpression was linked to short overall survival times (P =.0129). The value of bcl-xL gene expression as a prognostic marker in follicular lymphoma should thus be considered.
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PMID:Prognostic significance of bcl-xL gene expression and apoptotic cell counts in follicular lymphoma. 1296 62

The majority of follicular lymphoma and Burkitt's lymphoma are associated with reciprocal translocations involving BCL2 and cMYC, respectively. Unusual reports of aggressive lymphoma presenting with both translocations have been described as well as rare cases with a third structural alteration usually involving BCL6. The patient described here presented with aggressive high-grade lymphocytic leukemia, FAB subtype L2 (ALL-L2), and three reciprocal translocations, t(14;18)(q32;q21), t(8;14)(q24.1;q32), and t(1;2) (q22-23;p13). Despite immature morphology the leukemic blasts had a mature B-cell phenotype; they were positive for surface immunoglobulin heavy chains and negative for CD34, TdT, and CD10. Most reported dual t(14;18)/t(8;14) cases have not shown sIg and were positive for CD10. Molecular genetic analyses showed the typical rearrangements of BCL2 and cMYC as well as the FCGR2B gene on chromosome 1q23. The occurrence of a third oncogene rearrangement in association with the dual BCL2, cMYC translocations in ALL patients is very rare. To our knowledge, this is the first case where the third hit involves the FCGR2B locus. This report reiterates the poor prognosis associated with activation of cMYC together with elevated Bcl-2 expression. These data also support recent evidence that dysregulation of FCGR2B may play a role in tumor progression.
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PMID:Case of acute lymphoblastic leukemia presenting with t(14;18)/BCL2, t(8;14)/cMYC, and t(1;2)/FCGR2B. 1450 97

The bcl-2 gene codes for a protein which functions to inhibit apoptotic cell death, that involves an intrinsic normal cell death program. Bcl-2 overexpression was originally described in a follicular lymphoma, but more recently bcl-2 expression has been observed in a variety of other human neoplasms. Variation in the frequency of apoptosis in hormone-sensitive tissues, such as the endometrium, is known to occur as a result of hormonal changes in both physiological and pathological circumstances. In this study we examined bcl-2 protein expression in a total of 170 samples of endometrial tissues (18 proliferative endometrium, 14 secretory endometrium, 35 adenomatous hyperplasia and 103 carcinomas). The results were compared with p53, pRb and c-erbB-2 proteins expression, estrogen and progesterone receptors status, with the proliferative activity and with clinicopathological features. The expression of bcl-2 protein was lower in the group of carcinomas, when compared with the cases of adenomatous hyperplasia (p < 0.0001), normal proliferative (p < 0.0001) and secretory endometrium (p = 0.07). In normal proliferative endometrium bcl-2 expression was correlated with PCNA (p = 0.026) and in secretory endometrium it was correlated with ER status (p = 0.042). In hyperplasias, bcl-2 was correlated with PCNA (p = 0.019) and the PR (p = 0.007) expression. In carcinomas, decreased bcl-2 expression was associated with increased tumor grade (p = 0.04). A positive relationship between bcl-2 expression and pRb, as well as PCNA score (p = 0.014 and p = 0.001, respectively), was also found. These results indicate that bcl-2 expression may play a role in the inhibition of apoptosis in endometrial carcinoma and its expression seems to be associated with tumor differentiation and cell proliferation.
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PMID:Immunohistochemical study of apoptosis-related Bcl-2 protein and its correlation with proliferation indices (Ki67, PCNA), tumor suppressor genes (p53, pRb), the oncogene c-erbB-2, sex steroid hormone receptors and other clinicopathological features, in normal, hyperplastic and neoplastic endometrium. 1459 11

Lack of apoptosis has been linked to prolonged survival of malignant B cells expressing bcl-2. The aim of the present study was to analyze the amount of bcl-2 protein expressed along normal human B-cell maturation and to establish the frequency of aberrant bcl-2 expression in B-cell malignancies. In normal bone marrow (n=11), bcl-2 expression obtained by quantitative multiparametric flow cytometry was highly variable: very low in both CD34(+) and CD34(-) B-cell precursors, high in mature B-lymphocytes and very high in plasma cells. Bcl-2 expression of mature B-lymphocytes from peripheral blood (n=10), spleen (n=8) and lymph node (n=5) was significantly higher (P<0.02) in CD23(-) as compared to CD23(+) B cells, independent of the type of tissue analyzed. Upon comparison with normal human B-cell maturation, bcl-2 expression in neoplastic B cells from 144 patients was found to be aberrant in 66% of the cases, usually corresponding to bcl-2 overexpression (63%). Follicular lymphoma (FL) carrying t(14;18) and MALT lymphoma were the only diagnostic groups constantly showing overexpression of bcl-2. Bcl-2 overexpression was also frequently found in precursor B-acute lymphoblastic leukemia (84%), typical (77%) and atypical (75%) B-cell chronic lymphocytic leukemia, prolymphocytic leukemia (two of three cases), mantle cell lymphoma (55%), but not in t(14;18)(-) FL, splenic marginal zone lymphoma, Burkitt lymphoma and multiple myeloma.
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PMID:Quantitative analysis of bcl-2 expression in normal and leukemic human B-cell differentiation. 1472 50

Follicular lymphoma is an indolent lymphoma characterized by the (14;18) translocation, which leads to aberrant expression of Bcl-2. Translocations involving 8q24 are most commonly associated with Burkitt lymphoma and result in c-Myc overexpression. We report a case of follicular lymphoma of predominant small cleaved-cell type (grade 1) associated with both a t(14;18)(q32;q21) and a t(8;22)(q24;q11). The 8q24 translocation predicted an aggressive clinical course, as the lymphoma transformed into acute lymphoblastic leukemia within a year of initial diagnosis. Routine cytogenetic analysis is recommended at initial diagnosis of follicular lymphoma to better identify abnormalities that may predict prognosis and influence therapy.
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PMID:Follicular lymphoma with a burkitt translocation--predictor of an aggressive clinical course: a case report and review of the literature. 1473 81

Heterodimerization of antiapoptotic and pro-apoptotic Bcl-2 family of proteins provides an important mechanism for apoptosis regulation. Knowledge about key amino acids in the binding groove of native Bcl-2 contributing to this interaction will greatly facilitate the design of Bcl-2-specific inhibitors. There are two different Bcl-2 sequences, M13994 and M14745, in Genbank. Chimeric proteins Bcl-2(1) and Bcl-2(2) derived from the above sequences, although similar in structure, showed different binding affinities to Bak and Bad BH3 peptides (Petros et al., 2001). In this study, we show that the Bcl-2(1) sequence in normal and tumor human tissue samples differs from M13994 and M14745, and contains P59, T96, R110, S117 and G237. The actual sequence in the binding pocket matches the Bcl-2-Ig fusion sequence X06487, originally identified in a t(14:18) translocation of the Bcl-2 gene, associated with follicular lymphoma. The possible effects of the observed amino acid differences compared to M13994 and M14745 were investigated by combining structural data with fluorescence anisotropy. G110R substitution confers on Bcl-2(1) substantially increased binding affinity to Bak, Bad and Bax BH3 peptides, demonstrating that R110 is a key contributor to the BH3 binding affinity of Bcl-2. Although NMR structure did not predict R110 involvement in binding to these BH3 peptides, fluorescence anisotropy data clearly points to a critical role for this residue in binding to pro-apoptotic Bcl-2 family members.
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PMID:Divergence of Genbank and human tumor Bcl-2 sequences and implications for binding affinity to key apoptotic proteins. 1473 18

A P-ethoxy oligonucleotide (oligo), 20 bases long and specific for the translation initiation site of human Bcl-2 mRNA, was incorporated into liposomes to increase its intracellular delivery. This oligo selectively inhibited Bcl-2 protein expression and induced growth inhibition in t(14;18)-positive transformed follicular lymphoma (FL) cell lines. We studied the inhibitory effects of shorter liposomal P-ethoxy oligos (7, 9, 11 or 15 mer) in order to determine the activity of different oligo chain lengths targeted to the same Bcl-2 mRNA. At 12 microM, all the oligos inhibited the growth of a FL cell line. We compared the 7-mer oligo with the 20-mer oligo. The two oligos inhibited Bcl-2 protein expression similarly: 66% and 60% for the 7- and 20-mer, respectively. The uptake and retention of both oligos were also very similar. Our results indicate that the Bcl-2 inhibitory activity is maintained with P-ethoxy antisense oligos ranging from 7 to 20 bases.
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PMID:Cellular pharmacology of P-ethoxy antisense oligonucleotides targeted to Bcl-2 in a follicular lymphoma cell line. 1473 53

Overexpression of Bcl-2 protein has been known to play a role in the pathogenesis of follicular lymphoma (FL). However, 10-15% of FLs are negative for Bcl-2 by immunohistochemistry, raising the possibility that another gene product(s) may provide prosurvival signal(s). We used reverse phase protein microarray to analyze lysates of follicle center cells isolated by laser capture microdissection from: Bcl-2+ FL, Bcl-2- FL and reactive follicular hyperplasia (FH) (nine cases each group). TUNEL assay confirmed similar and reduced levels of apoptosis in Bcl-2+ FL and Bcl-2- FL, indicating the likelihood of Bcl-2-independent inhibition of apoptosis. Arrays were quantitatively analyzed with antibodies to proteins involved in the apoptotic pathway. As expected, Bcl-2 levels were up to eight-fold higher in Bcl-2+ FL than in FH and Bcl-2- FL. However, there was no difference in levels of Mcl-1 and survivin among these three groups. Bcl-X(L) showed a trend for increased expression in Bcl-2- FL as compared with Bcl-2+ FL, although the differences did not reach statistical significance (P>0.1). The increase in Bcl-X(L) may provide an alternative antiapoptotic signal in FL negative for Bcl-2 protein. Interestingly, Bax expression was higher in FL (Bcl-2+ or -) than in FH (P=0.001). Notably, phospho-Akt (Ser-473) was increased in FL (Bcl-2+ or -) (P<0.03) with increased phospho-Bad (Ser-136), as compared with levels in FH. The activation of the Akt/Bad pathway provides further evidence of prosurvival signals in FL, independent of Bcl-2 alone. These data suggest that nodal FL represents a single disease with a final common biochemical pathway.
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PMID:Similarities of prosurvival signals in Bcl-2-positive and Bcl-2-negative follicular lymphomas identified by reverse phase protein microarray. 1476 88


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